Pahlavi vs Iranian language

Pahlavi and Iranian language both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pahlavi	Yes	No	No	No
Iranian language	Yes	No	No	No

As nouns, Iranian language is a hypernym of Pahlavi; that is, Iranian language is a word with a broader meaning than Pahlavi:

Pahlavi: the Iranian language of the Zoroastrian literature of the 3rd to 10th centuries
Iranian language: the modern Persian language spoken in Iran

Other hypernyms of Pahlavi include Iranian.

Pahlavi (noun)	Iranian language (noun)
the Iranian language of the Zoroastrian literature of the 3rd to 10th centuries	the modern Persian language spoken in Iran
the script (derived from the Aramaic alphabet) used to write the Pahlavi language
Shah of Iran who was deposed in 1979 by Islamic fundamentalists (1919-1980)